Field of the Invention
The present invention relates to a feeding device and an image forming apparatus.
Description of the Related Art
Conventionally, an image forming apparatus such as a copying machine, a printer, and a facsimile machine includes a feeding device for feeding sheets to an image forming unit. The feeding device is provided with a sheet storage device that stores sheets to be fed. An example of the sheet storage device is a feeding cassette detachably attached to the image formation apparatus.
A feeding cassette discussed in Japanese Patent Application Laid-Open No. 2013-180842 is illustrated in FIG. 19. An intermediate plate (stacking member) 901 in a feeding cassette 900 is provided in a casing 903 to be rotatable in a vertical direction around a rotating shaft 903a. A lifting plate 902 pushes up the downstream side of the intermediate plate 901 in a feeding direction of the sheets S. Thus, the sheet S stacked on the intermediate plate 901 contact a pickup roller (feeding member) 904 with a predetermined pressing force. The sheet S, which has been pushed up by the intermediate plate 901, is fed by the pickup roller 904, and is sent out in a stable state by a conveyance roller 905 on the downstream side thereof. Japanese Patent Application Laid-Open No. 2013-180842 discusses lifting up the intermediate plate 901 when a sheet surface detection member contacting upper surface of the sheets S detects that the height of the uppermost surface of the sheets S has been lowered. In this way, the height of the uppermost surface of the sheets S can be kept within a predetermined range, and a feeding condition can be stabilized.
Japanese Patent Application Laid-Open No. 2012-030956 discusses raising and lowering a pickup roller relative to stacked sheets using a driving force of a driving source.